TRANSPORT PROTECTS IN BULK MALT
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By P. A. C. Brockington, A.M.I.Mech.E.
pROTECT1ON of his load against the effects of a damp atmosphere is the first consideration of the maltster when he is deciding upon the best method of transport to employ. If malt is exposed to damp air for any length of time its moisture content rises above the breweries' 2.5 per cent. limit.
There is, therefore, little latitude with regard to moisture up-take. A suitably designed bulk vehicle facilitates protection, in addition to producing the more usual advantages associated with bulk deliveries.
Samuel Thompson and Sons, Ltd., Langley Green, Birmingham, are among the many companies controlled by Associated British Maltsters, Ltd., who operate maltings in Yorkshire, the Midlands, Lincolnshire, Norfolk, Suffolk, Somerset, Wiltshire and Gloucestershire.
A substantial proportion of the total output of malt in the country is produced by the group, who employ hulk transport to the greatest possible extent. The practical interest of the Samuel Thompson concern in bulk carriers is representative of this policy.
In 1952, Mr. S. G. Thompson, a director, had discussions with the technical staff of I. FL Sparshatt and Sons, Ltd., Portsmouth, regarding the carriage of malt in bulk. As a result, a prototype tipping semi-trailer was evolved and built by Sparshatt in collaboration with Mr. Thompson.
It was planned to prevent the ingress of moisture and to enable such a rapid discharge rate to be employed that damp air would have little effect on the material when it was unloaded.
The vehicle has a capacity equivalent to 100 5-cu.-ft. sacks, which normally represents a load of 7itons. It is used in conjunction with a Dodge. 105 AP.6 tractor, and has now covered well over 100,000 miles.
The success of the prototype bulk carrier in operation, despite some limitations, confirmed the outstanding value n 12 of the type, and in 1955 two further vehicles were added to the fleet. They were equipped with similar body structures.
The first was a 100-sack articulated outfit, having a shorter body and fitted with Cranes oscillating axles, which is hauled by a Gardner-engined Foden tractor. The second was a rigid vehicle, based on a Foden eight-wheeled chassis and capable of carrying the equivalent of 200 sacks.
All the bodies were supplied by Sparshatt and are of light-alloy construction with external stiffening members. The body of the eight-wheeler is generally similar to that of the bulk-coal and coke carrier first produced in 1949 to a design evolved by Sparshatt in conjunction with the Northern Aluminium Co., Ltd., and the Southern Gas Board.
Corrugated alloy plank is extensively employed to increase the strength of the 200-sack body without sacrificing lightness, and the stability of the structure has been demonstrated ly
arduous runs with a test load of barley weighing 20 tons.
Malt has a natural angle of repose of 45' (at a reduced tilt it will not flow to a lower level) and all the body corners are shaped to this minimum angle. The body must be tipped for loading so that the loading hopper must be located at a greater height than is. normally necessary.
With the body fully tipped at an angle of 45°, the articulated outfits have all overall height of 16 ft. 3 in., and the maximum-load vehicle cannot pass under a hopper that is less than 18 ft' high.
Material is loaded through a hatch on the sloping forward end of the body, which is subsequently sealed by an airtight cover. Discharge from the hopper at the rear of the vehicle is controlled by two slides of different sizes, with which the rate of flow can be accurately ,adjusted to suit the customer's plant. The maximum rate of , discharge is equivalent to 100 sacks in 21 minutes.
The more conventional unloading installations include the conveyorelevator type, which normally allows a discharge rate of 100 sacks in 15 minutes, a suction plant and the open hopper. The hopper gives the highest rate of discharge.
When a suction plant is employed, the intake pipe fits direct into a special subsidiary slide, adjusted to control the grain delivery.
flow to the capacity of the plant. The maximum discharge rate is 100 sacks in 30 minutes. Unloading this amount of sacked material would occupy three or more men at least an hour.
Based at a main depot in Abingdon, the three vehicles are used for bulk deliveries from Abingdon, Bath, Salisbury and Gloucester, mainly to King's Langley, Park Royal, London and Birmingham. Each vehicle normally completes five runs in a week.
Advantages of bulk loading to the operator, apart from the easier control of moisture content, include the elimination of sacks—the 18 sackcarrying vehicles in the fleet necessitate the replacement of 5,000 sacks a year —and a reduction in the labour required for sacking-up, weighing and tying. • The 15-tOnner provides a longer run :for the screening machine, and the overall cost per ton-mile of carrying the malt is appreciably reduced.
Because of high capital costs, the vehicles have not enabled delivery costs to be reduced, and rising 'costs will probably preclude any reduction in the future, but Mr.Thompson envisages that the time will come when a customer has to pay a higher price for sacked malt than for material delivered in bulk.
The collection of barley from farms is organized by the merchants, and Samuel Thompson bulk vehicles are often employed if the necessary loading facilities are available. Delivery of malt in bulk to breweries averages between 22 per cent. and 25 per cent. of the total, but the proportion of barley collected in bulk is as yet a relatively small percentage of the overall tonnage moved.
A progressive increase is, however,
expected, and it is considered that more than 30 per cent. of both barley and malt will eventually be carried in bulk.
Two bulk grain articulated carriers are also used by the company. They were built by Conveyors (Ready Built), Ltd., of Stroud, Glos, and are particularly suited to farm collections. The bodies do not tip and have a capacity equivalent to 100 sacks. Equipped with a discharge conveyor, located below the floor, they have a rearmounted elevator, driven by a 3 h.p. air-cooled petrol engine. Material can be discharged by gravity at the rear or from a central outlet, and by the auxiliary elevator to a height of 12 ft or to a lower height in an equivalent radius of the discharge point. The semi-trailers are hauled by Foden tractors.
With the exception of the Dodge tractor of the 100-sack articulated bulk carrier, all the vehicles are of Foden manufacture. Every vehicle remains in the charge of the same driver and is returned to the makers for repairs during his holiday.
Drivers are regarded as important representatives of the company, and when a driver leaves the concern, which is unusual, he is replaced by one who has been recommended by the other drivers. The engagement of a new driver with the necessary high standard of ability and character has never caused any difficulty.